WO2014173755A1

WO2014173755A1 - Tool having cvd coating

Info

Publication number: WO2014173755A1
Application number: PCT/EP2014/057720
Authority: WO
Inventors: Dirk Stiens; Sakari Ruppi; Thorsten MANNS
Original assignee: Walter Ag
Priority date: 2013-04-26
Filing date: 2014-04-16
Publication date: 2014-10-30
Also published as: EP2989227A1; CN105247099A; JP6542753B2; KR20160002867A; KR102257864B1; CN105247099B; EP2989227B1; DE102013104254A1; US20160053372A1; US9976213B2; ES2684410T3; JP2016522323A

Abstract

The invention relates to a tool having a base body made of carbide, cermet, ceramic, steel or high speed steel and a single or multiple layer wear-protection coating applied thereto in the CVD process, wherein the wear-protection coating has at least one Ti_1-xAl_xC_yN_z layer having stochiometric coefficients 0.70 < x < 1, 0 < y < 0.25 and 0.75 < z < 1,15, wherein the Ti_1-xAl_xC_yN_z layer has a thickness in the range from 1 μm to 25 μm and has a crystallographically preferred orientation, which is characterized by a ratio of the intensities of the x-ray diffraction peaks of the crystallographic {111} plane and the {200} plane, wherein l{111} / I{200} > 1 +h (In h)², wherein h is the thickness of the Ti_1-xAl_xC_yN_z-layer in "μm."

Description

Tool with CVD coating

Subject of the invention

The invention relates to a tool having a base body made of cemented carbide, cermet, ceramic, steel or high-speed steel and a single or multi-layer wear protection coating applied thereto by the CVD method, the wear protection coating having at least one Tii-xAl _x CyN _z layer with stoichiometric coefficients 0, 70 <x <1, 0-y <0.25 and 0.75-z <1.5, and with a preferred crystallographic orientation. Furthermore, the invention relates to a method for producing such a tool.

Background of the invention

Cutting inserts for material processing, in particular for machining metal, consist of a substrate body made of hard metal, cermet, ceramic, steel or high-speed steel, which in most cases provided with a single or multi-layer hard coating to improve the cutting and / or wear properties is. The hard coating consists of superimposed layers of monometallic or mixed metallic hard material phases. Examples of monometallic hard material phases are TiN, TiC, TiCN and Al2O3. Examples of mixed metallic phases in which one metal is partially replaced by another in one crystal are TiAIN and TiAICN. Coatings of the aforementioned type are applied by CVD (chemical vapor deposition), PCVD (plasma assisted CVD) or PVD (physical vapor deposition).

It has been found that certain preferred orientations of crystal growth in the deposition in the PVD or CVD process can have particular advantages, wherein for different applications of the cutting insert also different preferred orientations of certain layers of a coating can be particularly advantageous. The preferred orientation of growth is usually related to the values defined by the Miller indices. indicated by the crystal lattice and referred to as a crystallographic texture (eg fiber texture).

DE 10 2005 032 860 discloses a hard material coating with a layer of cubic surface-centered Tii- _X Al _X N with an Al content of 0.75 <x <0.93 and a process for the production thereof.

DE 10 2007 000 512 discloses a hard material coating with a layer of TiAIN, which is deposited on a first layer of TiN, TiCN or TiC deposited directly on the substrate and with a phase gradient provided between the two layers. The TiAIN layer has a preferential orientation of crystal growth relative to the (200) plane of the crystal lattice.

The published patent applications WO 2009/1 121 15, WO 2009/1 121 16 and WO 2009/1 121 17A1 disclose TiAIN and TiAICN layers deposited by means of CVD processes with a high Al content and cubic face-centered lattice, but are not crystallographic Preferred orientations of crystal growth described.

TiAIN coatings prepared by PVD processes with different crystallographic preferences of crystal growth are known, however, cubic face-centered PVD coatings of TiAIN coatings are limited to Al contents of less than 67%, unlike CVD coatings. TiAIN coatings with a crystallographic preferential orientation of the {200} plane with respect to the growth direction of the crystallites are described as being advantageous for metal working (eg US 2009/0274899, US 2009/0074521 and WO 2009/127344).

OBJECT The object of the present invention was to provide cutting inserts for cutting metalworking, in particular the turning and milling of steel or cast materials, which have an improved wear resistance compared with the prior art. Description of the invention

This object is achieved by a method for producing a tool having a base body made of hard metal, cermet, ceramic, steel or high-speed steel and a one or more layers of CVD applied wear protection coating, wherein the wear protection coating at least one Tii-xAl _x CyN _z Layer has with stoichiometric coe efficient 0.70 <x <1, 0-y <0.25 and 0.75 <z <1, 15 and with a thickness in the range of 1 μιτι to 25 μιη, wherein for the production of Tii -xAl _x CyN _z position

a) the bodies to be coated are placed in a substantially cylindrical CVD reactor designed to flow the bodies to be coated against the process gases in a direction substantially radial to the longitudinal axis of the reactor, b) two precursor gas mixtures (VG1) and (VG2), wherein

the first precursor gas mixture (VG1)

0.005% to 0.2% by volume of TiCl ₄ ,

0.025% to 0.5% by volume AlC and

as carrier gas hydrogen (H2) or a mixture of hydrogen and nitrogen

Contains (H2 / N2) and

the second precursor gas mixture (VG2)

0.1 to 3.0% by volume of at least one N donor selected from ammonia (NH 3) and hydrazine (N ₂ H ₄ ), and

as carrier gas hydrogen (H2) or a mixture of hydrogen and nitrogen

Contains (H2 / N2),

and the first precursor gas mixture (VG1) and / or the second precursor gas mixture (VG2) optionally, a C-donor selected among acetonitrile (CH3CN), ethane (C2H6), ethene (C 2 H ₄₎ and acetylene (C2H2), and mixtures thereof, wherein the total vol.% of N donor and C donor in the precursor gas mixtures (VG1, VG2) is in the range of 0.1 to 3.0 vol.%,

c) the two precursor gas mixtures (VG1, VG2) are kept separate before entering the reaction zone and at a process temperature in the CVD reactor in the range of 600 ° C to 850 ° C and a process pressure in the CVD reactor in the range of 0.2 until 18 kPa are introduced substantially radially to the longitudinal axis of the reactor,

wherein the ratio of the volume gas flows (v) of the precursor gas mixtures (VG1, VG2) v (VG1) / v (VG2) is less than 1.5. For the purposes of the present invention, percentages by volume in the precursor gas mixtures relate to the total volume of the gas mixture introduced into the reaction zone from the first and second precursor gas mixtures. It has surprisingly been found that the process according to the invention Tii-xAlxCyN _z - and Tii- _X Al _X N _Z layers with stoichiometric 0.70 <x <1, 0 <y <0.25 and 0.75 -Ξ z < 1, 15 and can be prepared with cubic face-centered lattice having a pronounced preference of crystal growth with respect to the {1 1 1} plane of the crystal lattice. In comparison with known coatings with TiAICN and TiAIN layers, in particular those with preferred orientation of the crystal growth with respect to the {200} plane of the crystal lattice, the coatings according to the invention have outstanding properties in metalworking. It has further been found, surprisingly, that in a cutting insert having a coating of the type described herein in metal cutting operations, particularly in turning and milling of steel or cast materials, improved wear resistance over a known cutting insert and a wider range of applications can be achieved ,

The CVD process of the present invention provides two precursor gas mixtures (VG1) and (VG2) wherein the first precursor gas mixture (VG1) contains the metals Ti and Al in the form of their chlorides and carrier gas and the second precursor gas mixture (VG2) contains at least one N donor contains. For the production of a pure TiAIN layer usually only N-donor ammonia (NH3) or hydrazine (N2H4) is used. For the preparation TiAICN layer N-donor and C-donor are used, for example ammonia (NH3) mixed with ethene (C2H4). Acetonitrile (CH 3 CN) acts predominantly as C donor in the process according to the invention and is therefore used in admixture with an N donor. Depending on the desired stoichiometry, mixtures with other N donors and C donors can be used. The process of the present invention requires that the N-donor be supplied separately from the chlorides of the metals Ti and Al, while the C donor may be supplied via both the first precursor gas mixture (VG1) and the second precursor gas mixture (VG2). In a further preferred embodiment of the invention, the N-donor is ammonia (NH3).

The inventively used CVD process is an MT-CVD process at a process temperature in the CVD reactor in the range of 600 ° C to 850 ° C and a process pressure in the range of 0.2 to 18 kPa. The CVD reactor is a substantially cylindrical reactor, which is designed for an influx of the bodies to be coated with the process gases in a direction substantially radially to the longitudinal axis of the reactor, ie from the central axis of the cylindrical reactor in the direction of the outer wall of the reactor formed by the cylinder jacket. Such cylindrical reactors are known and commercially available, for example the Bernex® BPXpro CVD coating systems from Ionbond AG Ölten, Switzerland. An essential method of the process of the invention is that the two precursor gas mixtures (VG 1) and (VG2) are kept separate prior to entering the reaction zone. If this is not done, the precursor gas streams may already react too early, for example in the supply lines, and the desired coating will not be achieved.

A further essential method measure of the method according to the invention is that the ratio of the volume gas flows (v) of the precursor gas mixtures (VG1, VG2) v (VG1) / v (VG2) is less than 1.5. If one selects the ratio of the volume gas flows (v) of the precursor gas mixtures (VG1, VG2) v (VG1) / v (VG2) greater than 1.5, one does not obtain the desired properties of the Tii-xAl _x CyN _z layer, especially not the Preferred orientation of crystal growth with respect to the {1 1 1} plane of the crystal lattice defined herein as the ratio of the intensities of the X-ray diffraction peaks 1 {1 1 1} / 1 {200} and according to the invention should be> 1 + h (In h) ² where h is the thickness of the Tii-xAl _x CyN _z layer in "μιτι". In a preferred embodiment of the invention, the process temperature in the CVD reactor is in the range of 650 ° C to 800 ° C, preferably in the range of 675 ° C to 750 ° C.

If the process temperature in the CVD reactor is too high, high levels of hexagonal AlN will be obtained in the layer, causing i.a. the layer hardness decreases.

On the other hand, if the process temperature in the CVD reactor is too low, the deposition rate may drop to an uneconomic level. In addition, layers with chlorine contents> 1 at.% And lower hardness are obtained at low temperatures. In a further preferred embodiment of the invention, the process pressure in the CVD reactor is in the range from 0.2 to 7 kPa, preferably in the range from 0.4 to 1.8 kPa.

If the process pressure in the CVD reactor is too high, this leads to an uneven layer thickness distribution on the tools with increased layer thickness at the edges, the so-called dogbone effect. In addition, high levels of hexagonal AIN are often obtained. A process pressure in the CVD reactor smaller than 0.2 kPa, however, is technically difficult to implement. In addition, if the process pressure is too low, uniform coating of the tools is no longer guaranteed. In a further preferred embodiment of the invention, the ratio of the volume gas flows (v) of the precursor gas mixtures (VG1, VG2) v (VG1) / v (VG2) is less than 1.25, preferably less than 1.15.

If the ratio of the volumetric gas flows (v) of the precursor gas mixtures (VG1, VG2) is too high, then a preferred {1 1 1} preference orientation is obtained as a rule.

In a further preferred embodiment of the invention, the concentration of TiCU in the precursor gas mixture (VG1) and the concentration of N-donor in the precursor gas mixture (VG2) are adjusted so that the molar ratio of Ti to N in the in step c) volumetric gas flows introduced into the reactor are v (VG1) and v (VG2) <0.25.

It has surprisingly been found that at a higher molar ratio of Ti to N of the volumetric gas streams v (VG1) and v (VG2) introduced into the reactor, very Ti-rich layers are obtained, especially when using ammonia (NH3) as N-donor , It is believed that if the ratio of Ti to N in the bulk gas flows is too high, the reaction of the AICI3 is suppressed due to complex formation between TiCU and the N-donor.

In a further preferred embodiment of the invention, the second precursor gas mixture (VG2) contains <1, 0 vol .-%, preferably <0.6 vol .-% of the N-donor.

If the concentration of the N donor, optionally in admixture with C donor, in the second precursor gas mixture (VG2) is too high, the desired composition and preferential crystallographic orientation will not be obtained.

In a further preferred embodiment of the invention, the Verschleißschutzbe- coating a blasting treatment with a particulate blasting medium, preferably corundum, subjected to conditions that the Tii-xAl _x Cyn _z -layer according to the blasting treatment residual stresses in the range of +300 to -5000 MPa, preferably in the range of -1 to -3500 MPa. If the compressive residual stress of the Tii-xAl _x CyN _z layer is too high, the coating may flake off at the edges of the tool.

However, if residual tensile stresses are present in the Tii-xAl _x CyN _z layer, the optimum resistance of the tool to thermomechanical alternating stress or to the formation of comb cracks is not achieved.

To introduce the preferred residual stresses into the Tii-xAl _x CyN _z layer, dry or wet blast treatment can be used with advantage. The blast treatment is expediently carried out at an abrasive medium pressure of 1 bar to 10 bar.

The duration of the jet treatment required for introducing the residual stresses according to the invention and the required jet pressure are parameters which the person skilled in the art can determine by simple experiments within the limits defined herein. A blanket statement is not possible here, since the self-adjusting residual stresses depend not only on the duration of the blast treatment and the jet pressure, but also on the structure and the thickness of the overall coating. However, the jet pressure has the much greater influence on the change in the residual stresses in the coating and the substrate body compared to the jet duration. Suitable jet treatment times are usually in the range of 10 to 600 seconds.

The beam angle, d. H. the angle between the treatment beam and the surface of the tool also has a significant influence on the introduction of residual stresses. At a beam angle of 90 °, the maximum entry of compressive residual stresses occurs. Lower beam angles, d. H. oblique irradiation of the blasting abrasive, lead to a stronger abrasion of the surface and lower pressure self-tension entry.

The invention also encompasses a tool having a base made of cemented carbide, cermet, ceramic, steel or high-speed steel and a single-layer or multi-layer wear protection coating applied thereto by the CVD method, the wear protection coating having at least one Tii-xAl _x CyN _z layer with stoichiometric coefficients 0 , 70 <x <1, 0-y <0.25 and 0.75 <z <1, 15, characterized in that

the Tii-x Alx C y N _z layer has a thickness in the range of 1 μm to 25 μm and has a crystallographic preferential orientation which is characterized by a ratio of the intensities of the X-ray diffraction peaks of the crystallographic {1 1} plane and the {200} plane is characterized in which l {1 1 1} / 1 {200}> 1 + h (In h) ² , where h is the thickness of the Tii-xAl _x C _y N _z layer in "μιτι". In a preferred embodiment of the invention, the half-width (FWHM) of the X-ray diffraction peak of the {1 1 1} plane of the Tii-xAl _x CyN _z layer is <1 °, preferably <0.6 °, particularly preferably <0.45 °.

Too high a half width (FWHM) of the X-ray diffraction peak of the {1 1 1} plane of the ThxAlxCyNz layer indicates smaller grain sizes of the cubic face centered (fcc) phase or even amorphous phases. This has proven in the previous tests as a disadvantage for the wear resistance.

In a further preferred embodiment of the invention, the Tii-xAl _x CyN _z layer has at least 90% by volume Tii-xAl _x CyN _z phase with cubic face-centered (fcc) lattice, preferably at least 95% by volume Tii _x Al _x CyNz phase with cubic face-centered (fcc) lattice, more preferably at least 98% by volume Tii _x Al _x CyNz phase with cubic face centered (fcc) lattice.

If the content of Tiis _x Al _x CyNz phase with cubic face centered (fcc) lattice is too low, a lower wear resistance is observed. In a further preferred embodiment of the invention, the Tii _x Al _x CyNz layer has stoichiometric coefficients of 0.70 <x <1, y = 0 and 0.95 <z <1.15.

In a further preferred embodiment of the invention, the TII _x Al _x C _y N _z -layer has a thickness in the range of 3 to 20 μιη μιη, preferably in the range 4-15 μιη on.

If the thickness of the Ti _x Al _x C _y N _z layer is too low, the wear resistance of the tool is not sufficient.

On the other hand, if the thickness of the Ti _x Al _x C _y N _z layer is too high, the layer may flake off due to the thermal internal stresses after the coating.

In a further preferred embodiment of the invention, the ratio of the intensities of the X-ray diffraction peaks of the crystallographic {1 1 1} plane and the (200) plane of the Tii-xAl _x CyN _z layer is> 1 + (h + 3) x (ln h) ² . In a further preferred embodiment of the invention, the Tii-xAl _x CyN _z layer has a Vickers hardness (HV)> 2300 HV, preferably> 2750 HV, particularly preferably> 3000 HV.

In a further preferred embodiment of the invention, at least one further layer of hard material is arranged between the base body and the Tii-xAl _x CyN _z layer, selected from a TiN layer, one by means of high-temperature CVD (CVD) or medium-temperature CVD (MT-CVD ) deposited TiCN layer, a

and combinations thereof. It is particularly preferable to apply the further layers in the same temperature range, ie by medium-temperature CVD (MT-CVD) as the Tii-xAl _x CyN _z layer, in order to avoid uneconomical cooling times.

In a further preferred embodiment of the invention, at least one further layer of hard material is disposed above the Tii-xAl _x CyN _z layer, preferably at least one Al 2 O 3 layer of the modification Y-Al 2 O 3, K-Al 2 O 3 or O-Al 2 O 3, the Al 2 O 3 layer by means of high temperature CVD (CVD) or medium temperature CVD (MT-CVD). For the reasons mentioned above, it is particularly preferable to apply the aluminum oxide layer in the same temperature range, ie by means of medium temperature CVD (MT-CVD) as the Ti _x Al _x C _y N _z layer, in order to allow possible phase transformations of the Tii _{. x} Al _x C _y N _z position to avoid. Processes for the production of γ-Al 2 O 3, K-Al 2 O 3 or Al 2 O 3 layers in the range from 600 to 850 ° C. are known to the person skilled in the art, for example from EP 1 122 334 and EP 1 464 727.

In a further preferred embodiment, the preferred crystallographic orientation of the {1 1 1} plane of the _fcc-Tii-x Al _x C _y N _z -layer is so pronounced that the measured X-ray crystallography or by EBSD absolute maximum of the {1 1 1} -lntensität the fcc _Tii-x Al _x C _y N _z -layer = ± 10 °, preferably within α = ± 5 °, more preferably within a = ± located within an angular range of α 1 °, starting from the normal direction to the sample surface , Decisive here is the section through the {1 1 1} pole figure of the fcc Tii _-x Al _x C _y N _z after integration of the intensities on the azimuth angle ß (rotation angle around the sample surface normal).

Description of the figures

Figure 1: cutting edge of an indexable insert with coating no. 9 according to the prior art after a rotation test;

Figure 2: cutting edge of an indexable insert with coating No. 8 according to the prior art after a rotation test; FIG. 3: Cutting edge of an indexable insert with Tii-xAl _x CyN _z according to the invention

Coating No. 1 after a twist test;

FIG. 4: X-ray diffractogram of coating No. 4 (invention);

FIG. 5: X-ray diffractogram of coating No. 8 (prior art);

FIG. 6: Inverse pole figure for the normal direction of the coating No. 1 (invention);

Figure 7: section through pole figure of the X-ray diffractogram after integration over the ß

Coating No. 1 (Invention);

FIG. 8: section through the pole figure of the X-ray diffractogram after integration over the coating No. 2 (invention).

Examples

Production of coated carbide indexable inserts

As substrate body, carbide indexable inserts of the geometry CNMA120412 with a composition of 86.5% by weight of WC, 5.5% by weight of Co, 2% by weight of TiC, 6% by weight (NbC + TaC ) and used with a mixed carbide-free edge zone. To coat carbide indexable inserts, a Bernex BPX325S CVD coater with a reactor height of 1250 mm and a reactor diameter of 325 mm was used. The gas flow was radial to the longitudinal axis of the reactor.

To connect the Tii-xAl invention Cyn _x _z plies and Comparative layers was un- first applied indirectly to the cemented carbide substrate, a μιη about 0.3 thick TiN layer or TiCN layer by CVD under the deposition conditions indicated in Table 1:

Table 1: Reaction conditions in the preparation of tails

To prepare the Tii-xAl _x CyN _z layers according to the invention, a first precursor gas mixture (VG1) with the starting compounds TiCU and AlC and a second precursor gas mixture were prepared. Mixed (VG2) with the starting compound NH3 as a reactive nitrogen compound separated from each introduced into the reactor, so that a mixing of the two gas streams took place only when it enters the reaction zone. The volume gas flows of the precursor gas mixtures (VG1) and (VG2) were adjusted so that when producing coatings according to the invention, the ratio of the volume gas flows v (VG1) / v (VG2) was less than 1.5. The parameters in the preparation of inventive Tii-xAlxCyN _z coatings and comparative coatings are shown in Table 3.

Preparation of comparative coatings

As further comparative examples according to the prior art were carbide inserts

a) a 12 μιτι thick layer system of sequence TiN / MT-Ti (C, N) / TiN (coating no. 9) and b) a 5 μιη thick layer system of the sequence TiN / MT-Ti (C, N) (coating no 10). For this purpose, the deposition conditions according to Table 2 below were used:

Table 2: Reaction conditions in the preparation of Coating Nos. 9 and 10 (Cf.)

To study the composition, texture, residual stresses and hardness of the coatings, the following procedures were used.

To determine the crystallographic preferred orientation, both X-ray diffraction (XRD) and electron diffraction methods, in particular EBSD, can be used. For the reliable determination of a preferred orientation, diffraction measurements of reflections are zelner surfaces {hkl} not suitable, but it must the Orientierungsdichtefunktion (ODF) are determined. Their representation in the form of an inverse pole figure shows the location and sharpness of any existing fiber texture. The orientation density function must either be constructed from statistically sufficiently many individual orientation measurements (in the case of EBSD) or from measurements of a minimum number of pole figures at different reflections {hkl} (with XRD). See: L. Spieß et al., Modern X-ray diffraction, 2nd edition, Vieweg & Teubner, 2009.

In the Tii- _x Al _x CyN _z layers according to the invention, it was verified by XRD measurement of a pole figure set and ODF calculation that a fiber texture with fiber axis was either exactly in the <1 1 1> direction or in a crystallographic direction of <10 ° Angular deviation of <1 1 1> is present. To quantify this texture, the intensity ratio of {1 1 1} and {200} reflections from θ-29 measurements can be used. The position of the fiber axis can be determined from the inverse pole figure or the X-ray measured pole figure of the {1 1 1} reflection.

X-ray iffractometry

X-ray diffraction measurements were taken on a GE Sensing & Inspection Technologies PTS3003 diffractometer using CuKa radiation. For Θ-2Θ residual stress and pole figure measurements, a parallel beam optic was used, which consisted on the primary side of a polycapillary and a 2 mm pinhole as a collimator. On the secondary side, a parallel plate collimator with 0.4 ° divergence and a nickel Kp filter was used. Peak intensities and half-widths were determined by 9-29 measurements. After subtracting the background, pseudo-Voigt functions were fitted to the measured data, whereby the Koi2 extraction was performed by means of Kai / Ka2 doublet adaptation. The values of the intensities and half-widths listed in Table 4 refer to the Kou interferences thus applied. The lattice constants are calculated according to the Vergard law, assuming the lattice constants of TiN and AIN from the PDF maps 38-1420 and 46-1200, respectively.

Differentiation between cubic face-centered (fcc) Ti- _X Al _X C _Y N ₇ and hexaqonal AlN

The {101} or {202} interpolations of hexagonal AIN and the {1 1 1} or {222} reflections of cubic Tii-xAl _x CyN _z may be more or less superimposed depending on their chemical composition. Only the interference of the {200} plane of the cubic Tii-xAl _x CyN _z is through no further interference, such as B. by the substrate body or above or below arranged layers superimposed and has for random orientation the highest intensity.

To assess the volume fraction of hexagonal AIN in the measurement volume and to avoid misinterpretations regarding the {1 1 1} and {200} intensities of the cubic Tii-xAl _x CyN _z , measurements (θ-29 scans) were taken at two different tilt angles ψ (ψ = 0 ° and ψ = 54.74 °) performed. Since the angle between the plane normals of {1 1 1} and {200} is about 54.74 °, with a strong {1 1 1} fiber texture, an intensity maximum of the {200} reflection at the tilt angle ψ = 54, 74 °, while the intensity of the {1 1 1} reflection approaches zero. Conversely, at the tilt angle ψ = 54.74 °, a strong intensity maximum of the {1 1 1} reflection is obtained for a strong {200} fiber texture, while the intensity of the {200} reflection approaches zero.

For the textured layers prepared according to the examples, it is possible in this way to check whether the measured intensity at 2Θ~38.1 ° can be attributed primarily to the cubic face-centered Tii-xAlxCyN _z phase or whether larger fractions of hexagonal AlN in the layer are included. Both X-ray diffraction measurements and EBSD measurements consistently show only very small proportions of hexagonal AIN phase in the layers according to the invention.

Polfiquren

Pole figures of the {1 1 1} reflection were at 29 = 38.0 ° over an angular range of 0 ° <a <75 ° (increment 5 °) and 0 ° <ß <360 ° (increment 5 °) in a circular arrangement Measuring points created. The intensity distribution of all measured and recalculated pole pieces was approximately rotationally symmetric, i. the examined layers had fiber textures. To check the preference orientation, pole figures were measured on the {200} and {220} reflections in addition to the {1 1 1} pole figure. The orientation density distribution function (ODF) was calculated using the LaboTex 3.0 software from LaboSoft, Poland, and the preferred orientation was displayed as an inverse pole figure. In the layers according to the invention, the intensity maximum was in <1 1 1> direction or <10 ° angle deviation of <1 1 1>.

In order to perform the residual stress analysis according to the sin ² ijj method, the {222} interference of the face-centered cubic Tii-xAl _x CyN _z layer was used and at 25 ψ angles from -60 ° to 60 ° (Increment 5 °). After background subtraction, Lorentz polarization correction and K02 extraction (Rachinger separation), the line positions of the interferences were determined by adapting profile functions to the measured data. The elastic constants used were V2S2 = 1, 93 TPa ^-1 and Si = -0.18 TPa ^-1 . The residual stress in the WC phase of the cemented carbide substrate was determined in the same way by {201} interference using the elastic constants V2S2 = 1.66 TPa ^-1 and Si = -0.27 TPa ^-1 .

Residual stresses are usually expressed in units of megapascals (MPa), denoting residual stresses with a positive sign (+) and compressive residual stresses with a negative sign (-).

EDX measurements (energy dispersive spectroscopy)

EDX measurements were carried out on a Supra 40 VP scanning electron microscope from Carl Zeiss at 15 kV acceleration voltage with an INCA x-act EDX spectrometer from Oxford Instruments, UK.

Microhardness Determination The microhardness was measured according to DIN EN ISO 14577-1 and -4 using a universal hardness tester Fischerscope H100 from Helmut Fischer GmbH, Sindelfingen, Germany, on a cross-section of the coated bodies.

Strahlbehandlunq

The carbide indexable inserts coated in the examples were subjected to a compressed air dry jet treatment after the CVD coating. The residual stresses in the Tii-xAlxCyN _z layer and in the substrate (WC) were measured before and after the blast treatment. The beam parameters used and the measured residual stress values are given in Table 5.

* Average of measurements on 4 samples from different reactor positions * ^* ng = not measured

Table 5: Jet treatment and particle tension measurements of various coatings

Cutting experiments - turning

Carbide indexable inserts of geometry CNMA120412 with a composition of 86.5% by weight of WC, 5.5% by weight of Co, 2% by weight of TiC, 6% by weight (NbC + TaC) and with a mixed carbide Boundless edge zone were coated with the CVD coatings No. 1 and No. 8 shown in Table 3 and the coating No. 9 described above (TiN / MT-Ti (C, N) / TiN). The total layer thickness was about 12 μιτι for all tools. The cutting inserts were used for longitudinal turning operations under the following cutting conditions:

Workpiece material: cast iron GG25

Coolant: emulsion

Feed: f = 0.32 mm

Depth of cut: a = 2.5 mm

Cutting speed: v _c = 200 m / min

FIGS. 1 to 3 show the inserted cutting edges of the indexable inserts after an engagement time of t = 9 min. The two reversible snowboards according to the prior art (Figure 1: coating 9, Figure 2: coating 8) show extensive flaking of the layer along the cutting edge. In the reversible snow plate with the Tii-xAl _x CyN _z coating according to the invention (FIG. 3: coating 1), hardly any flaking can be observed.

Machining Experiments - Milling (1) Geometry SEHW1204AFN carbide inserts with a composition of 90.47 wt% WC, 8 wt% Co, and 1.53 wt% TaC / NbC were coated with the CVD shown in Table 3 Coatings No. 4 and No. 8 coated. The total layer thickness was about 1 1 μιη in all tools. Milling operations were carried out with the cutting inserts under the following cutting conditions:

Workpiece material: nodular cast iron GGG70 (strength 680 MPa)

Synchronous operation, dry machining

Tooth feed: f _z = 0.2 mm

Cutting depth: = 3 mm

Cutting speed: v _c = 185 m / min

Setting angle: κ = 45 ° Work intervention: a _e = 98 mm

Supernatant: u _e = 5 mm

Subsequently, the maximum wear mark width Vß.max at the main cutting edge after 3200 m milling path was determined:

Zerspanversuche - Fräsen (2) Carbide indexable inserts of geometry SEHW1204AFN with a composition of 90.47 wt .-% WC, 8 wt .-% Co and 1, 53 wt .-% TaC / NbC were with the CVD shown in Table 3 Coating No. 5 and coated with the above-described Coating No. 10 (TiN / MT-Ti (C, N)). Indexable inserts with Coating No. 5 were used on the one hand in an unirradiated state and on the other hand after a dry blast treatment with ZrO2 as a blasting medium in accordance with Sample S8 in Table 5. Milling operations were carried out with the cutting inserts under the following cutting conditions:

Workpiece material: cast iron GG25

Synchronous operation, dry machining

Tooth feed: f _z = 0.2 mm

Depth of cut: a = 3 mm

Cutting speed: v _c = 283 m / min

Setting angle: κ = 45 °

Work intervention: a _e = 98 mm

Supernatant: u _e = 5 mm

Subsequently, the mean wear mark width VB and the number of comb cracks at the main cutting edge after 2400 m milling path were determined: Coating No. Wear mark width VB Comb cracks

[Mm]

5 unirradiated (invention) 0.05 3

5 blasted (invention) 0.05 0

10 (prior art): 0.10 8

Zerspanversuche - Milling (3)

Carbide indexable inserts of geometry SEHW1204AFN with a composition of 90.47 wt.% WC, 8 wt.% Co and 1.53 wt.% TaC / NbC were coated with the CVD coating No. 5 as shown in Table 3 and coated with the coating No. 10 described above (TiN / MT-Ti (C, N)). For each coating variant, 3 cutting inserts were tested. Milling operations were carried out with the cutting inserts under the following cutting conditions:

Workpiece material: mild steel St37 (strength approx. 500 MPa)

Synchronous operation, dry machining

Tooth feed: f _z = 0.3 mm

Depth of cut: a = 6 mm

Cutting speed: v _c = 299 m / min

Setting angle: κ = 75 °

Work intervention: a _e = 50 mm

Supernatant: u _e = 350 mm

Subsequently, the number of comb breaks on the main cutting edge after 3200 m milling path was determined:

Coating No. Comb cracks

5 (invention) - 1 0

5 (Invention) - 2 0

5 (Invention) - 3 0

10 (prior art) - 1 4

10 (prior art) - 2 3

10 (prior art) - 3 3

Claims

P a n t a n s p r e c h e

Method for producing a tool having a base body made of cemented carbide, cermet, ceramic, steel or high-speed steel and a single-layer or multi-layer wear protection coating applied thereto by the CVD method, wherein the wear protection coating has at least one Tii-xAl _x CyN _z layer with stoichiometric coefficients 0.70 <x <1, 0-y <0.25 and 0.75 <z <1, 15 and with a thickness in the range from 1 μm to 25 μm, where for the preparation of the Ti x-Al _x CyN _z position

a) the bodies to be coated are placed in a substantially cylindrical CVD reactor, which is designed for an influx of the bodies to be coated with the process gases in a direction substantially radially to the longitudinal axis of the reactor,

b) two precursor gas mixtures (VG1) and (VG2) are provided, wherein

the first precursor gas mixture (VG1)

0.005% to 0.2% by volume of TiCl ₄ ,

0.025% to 0.5% by volume of AICI ₃ and

as carrier gas contains hydrogen (H2) or a mixture of hydrogen and nitrogen (H2 / N2) and

the second precursor gas mixture (VG2)

as the carrier gas hydrogen (H2) or a mixture of hydrogen and

Contains nitrogen (H2 / N2),

and the first precursor gas mixture (VG1) and / or the second precursor gas mixture (VG2) optionally a C donor selected from acetonitrile (CH ₃ CN), ethane (C ₂ H ₆ ), ethene (C ₂ H ₄ ) and ethyne (C ₂ H ₂ ) and mixtures thereof, wherein the total vol.% proportion of N donor and C donor in the precursor gas mixtures (VG1, VG2) is in the range of 0.1 to 3.0 vol.%,

wherein the ratio of the volume gas flows (v) of the precursor gas mixtures (VG1, VG2) v (VG1) / v (VG2) is less than 1.5. A method according to claim 1, characterized in that the process temperature in the CVD reactor in the range of 650 ° C to 800 ° C, preferably in the range of 675 ° C to 750 ° C and / or the process pressure in the CVD reactor in the range of 0.2 to 7 kPa, preferably in the range of 0.4 to 1, 8 kPa.

Method according to one of the preceding claims, characterized in that the ratio of the volume gas flows (v) of the precursor gas mixtures (VG1, VG2) v (VG1) / v (VG2) is less than 1.25, preferably less than 1.15.

Method according to one of the preceding claims, characterized in that the concentration of TiCU in the precursor gas mixture (VG1) and the concentration of N-donor in the precursor gas mixture (VG2) are adjusted so that the molar ratio of Ti to N in the in c) volumetric gas flows introduced into the reactor are v (VG1) and v (VG2) <0.25.

Method according to one of the preceding claims, characterized in that the second precursor gas mixture (VG2) <1, 0 vol .-%, preferably S 0.6 vol .-% of the N-donor.

Method according to one of the preceding claims, characterized in that the N-donor is ammonia (NH3).

Method according to one of the preceding claims, characterized in that the wear protection coating is subjected to a blast treatment with a particulate blasting agent, preferably corundum, under conditions that the Tii- _x Al _x CyNz layer after the blasting treatment residual stresses in the range of +300 to -5000 MPa, preferably in the range of -1 to -3500 MPa.

Tool having a base made of cemented carbide, cermet, ceramic, steel or high-speed steel and a one-layer or multi-layer wear protection coating applied thereon by the CVD method, the wear protection coating having at least one Tii-xAl _x CyN _z layer with stoichiometric coefficients of 0.70 - Ξ x <1, 0 S y <0.25 and 0.75 <z <1, 15, characterized in that

the Tii-xAlxCyNz layer has a thickness in the range from 1 μm to 25 μm and has a crystallographic preferred orientation characterized by a ratio of the intensities of the X-ray diffraction peaks of the crystallographic {1 1} plane and the {200} plane - in which {circle over (1)} 1 {200}> 1 + h (In h) ² , where h is the thickness of the Ti _x Al _x C _y N _z layer in "μιτι").

Tool according to claim 5, characterized in that the half-width (FWHM) of the X-ray diffraction peak of the {1 1 1} plane of the Tii-xAl _x CyN _z layer <1 °, preferably <0.6 °, particularly preferably <0.45 ° is.

Tool according to one of claims 8 or 9, characterized in that the Tii-xAlxCyNz layer at least 90 vol .-% Tii _x Al _x CyNz phase with cubic face-centered (fcc) lattice, preferably at least 95 vol .-% Tii _x Al _x CyNz phase with cubic face-centered (fcc) lattice, more preferably at least 98% by volume Tii _x Al _x CyN _z phase with cubic face centered (fcc) lattice.

Tool according to one of claims 8 to 10, characterized in that the Tii-xAlxCyN _z- layer stoichiometry coefficient 0.70 <x <1, y = 0 and 0.95 <z <1, 15 has.

Tool according to one of claims 8 to 1 1, characterized in that the Tii-xAlxCyN _z- layer has a thickness in the range of 3 μιη to 20 μιη, preferably in the range of 4 to 15 μιη.

Tool according to one of claims 8 to 12, characterized in that the ratio of the intensities of the X-ray diffraction peaks of the crystallographic {1 1 1} plane and the (200) plane of Tii- _x Al _x CyN _z layer> 1 + (h +3) x (ln h) is ² .

Tool according to one of claims 8 to 13, characterized in that the Tii-xAlxCyN _z- layer has a Vickers hardness (HV)> 2300 HV, preferably> 2750 HV, more preferably> 3000 HV.

Tool according to one of claims 8 to 14, characterized

in that at least one further layer of hard material is arranged between the base body and the Ti _x Al _x C _y N _z layer, selected from a TiN layer, one by means of high-temperature CVD (CVD) or medium-temperature CVD (MT-CVD) deposited TiCN layer, one and combinations thereof and / or

at least one further layer of hard material is arranged above the Ti _x Al _x C _y N _z layer, preferably at least one of the modification Y-Al 2 O 3, K-Al 2 O 3 or O 1-Al 2 O 3, particularly preferred is an aA.sub.OS layer, wherein the AC.sub.2 layer is deposited by means of high-temperature CVD (CVD) or medium-temperature CVD (MT-CVD).

Tool according to one of Claims 8 to 15, characterized in that the absolute maximum of the diffraction intensity of the crystallographic {1 1 1} planes of the fcc-Tii _x Al _x CyNz layer determined by X-ray analysis or by EBSD is within an angular range of a = ± 10 °, preferably within a = ± 5 °, more preferably within α = ± 1 °, starting from the normal direction of the sample surface.

Tool according to one of claims 8 to 16, produced according to one of claims 1 to 16.